<style>
   #buttonbar-container {
      width: 100%;
      height: 100%;
      padding: 5px !important;
   }
   .buttonbar-button {

      margin-left: 2px;
   }
</style>
<script id="buttonbar-layout-template" type="text/template">
   <button class="buttonbar-button" rel="0" id="button_a">Button A</button>
   <button class="buttonbar-button" rel="1" id="button_b">Button B</button>
   <button class="buttonbar-button" rel="2" id="button_c">Button C</button>
   <button class="buttonbar-button" rel="3" id="button_d">Button D</button>
</script>